POLYSTICTUS VERSICOLOR AS A WOUND 

 PARASITE OF CATALPA 



Neil E. Stevens 

 (With Plates 74 and 75, Containing 4 Figures) 



The wood rot of living catalpa caused by Polystictus versicolor 

 is the only really serious disease of the catalpa yet reported. 

 Polystictus versicolor is, of course, one of the most common 

 wood-rotting saprophytes, but as was pointed out by von Schrenk 

 (8) in 1902, it becomes on the catalpa a dangerous wound para- 

 site, growing with great rapidity in living trees, spreading up and 

 down the trunk from the point of infection, out into the branches 

 and even into the roots (8, p. 53). On living trees the fungus 

 produces sporophores in great abundance, but is rarely found 

 fruiting on dead catalpa; a fact which apparently led von Schrenk 

 to the conclusion that P. versicolor is unable to grow on dead 

 catalpa wood and that even when growing in a living tree stops 

 its growth when the tree is cut (8, p. 54). As the writer has 

 shown in a recent paper (7), however, Polystictus versicolor 

 may continue to grow on dead catalpa wood and under favorable 

 conditions may produce normal sporophores in considerable quan- 

 tity. 



The report of von Schrenk on the diseases of the hardy catalpa 

 was based largely on observations in two large plantations in 

 Crawford County, Kansas, the Hunnewell and Farlington plan- 

 tations. In fact, these two plantations, together with the other 

 large plantations in the eastern portion of Kansas, have served 

 as the basis for most of the work done in this country on the 

 artificial cultivation of the hardy catalpa. During the past year 

 (1911-1912) the writer has investigated the wood rots of the ca- 

 talpa in this region, with special reference to second growth 

 stands. In the course of this work it has become evident that 

 coppice shoots on partly decayed stumps are much less readily 

 infected than are branches of a partly decayed trunk, and that 



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